1. Field of the Invention
The present invention relates to an engine waste heat recovering and cooling apparatus mounted on a vehicle, and more particularly to the one that improves fuel efficiency of a vehicle with a simple configuration.
2. Description of the Related Art
A water-cooled internal combustion engine mounted on a vehicle such as an automobile has a cooling water channel, in which cooling water is circulated, around a combustion chamber or a cylinder. The cooling water is also circulated to a radiator to cool the cooling water by a heat exchange with a relative wind.
This cooling water is also passed through a heater core for warming a vehicle compartment.
There has been proposed a system of utilizing waste heat of an engine recovered by cooling water in order to enhance a fuel efficiency of a vehicle.
For example, Japanese Patent Application Laid-Open (JP-A) No. 2005-83225 describes that the temperature of transmission oil is increased by utilizing the temperature of cooling water of an engine in order to reduce a viscosity of the transmission oil, which reduces a friction loss so as to enhance fuel economy and switching operability.
In the technique described in JP-A No. 2005-83225, the cooling water passes through an engine body and a heater core for warming, and then, is introduced into an oil temperature adjusting unit of the transmission oil through a channel changeover valve.
JP-A No. 2004-301061 describes that, in order to promote warming upon a restart of an engine, cooling water is warmed in a storage tank, which is a heat storage container, and a cooling water channel is switched by a rotary three-way valve.
In the technique described in JP-A No. 2005-83225, the transmission oil can be heated only after a large volume of cooling water, circulating in the engine, the heater core, and the cooling water channel that communicates these units, is completely heated. Therefore, it takes a long time from the start of the engine to the start of heating the transmission oil, whereby it is difficult to improve fuel economy immediately after the start of driving the vehicle.
If the heat storage container described in JP-A No. 2004-301061 is added to the oil temperature adjusting unit described above, the transmission oil can be heated to enhance fuel economy immediately after the start of driving the vehicle. However, in this case, a heat storage container, a switching valve, and a peripheral water channel has to be provided, which presents a problem with mounting space, cost, and weight.